[PATCH V13 07/10] mmc: block: blk-mq: Add support for direct completion

From: Adrian Hunter
Date: Fri Nov 03 2017 - 09:22:46 EST

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For blk-mq, add support for completing requests directly in the ->done
callback. That means that error handling and urgent background operations
must be handled by recovery_work in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
drivers/mmc/core/block.c | 100 +++++++++++++++++++++++++++++++++++++++++------
drivers/mmc/core/block.h | 1 +
drivers/mmc/core/queue.c | 5 ++-
drivers/mmc/core/queue.h | 6 +++
include/linux/mmc/host.h | 1 +
5 files changed, 101 insertions(+), 12 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index e8be17152884..cbb4b35a592d 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2086,6 +2086,22 @@ static void mmc_blk_rw_recovery(struct mmc_queue *mq, struct request *req)
}
}

+static inline bool mmc_blk_rq_error(struct mmc_blk_request *brq)
+{
+ mmc_blk_eval_resp_error(brq);
+
+ return brq->sbc.error || brq->cmd.error || brq->stop.error ||
+ brq->data.error || brq->cmd.resp[0] & CMD_ERRORS;
+}
+
+static inline void mmc_blk_rw_reset_success(struct mmc_queue *mq,
+ struct request *req)
+{
+ int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
+
+ mmc_blk_reset_success(mq->blkdata, type);
+}
+
static void mmc_blk_mq_complete_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
@@ -2167,14 +2183,43 @@ static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req)
if (host->ops->post_req)
host->ops->post_req(host, mrq, 0);

- blk_mq_complete_request(req);
+ /*
+ * Block layer timeouts race with completions which means the normal
+ * completion path cannot be used during recovery.
+ */
+ if (mq->in_recovery)
+ mmc_blk_mq_complete_rq(mq, req);
+ else
+ blk_mq_complete_request(req);

mmc_blk_mq_acct_req_done(mq, req);
}

+void mmc_blk_mq_recovery(struct mmc_queue *mq)
+{
+ struct request *req = mq->recovery_req;
+ struct mmc_host *host = mq->card->host;
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+
+ mq->recovery_req = NULL;
+ mq->rw_wait = false;
+
+ if (mmc_blk_rq_error(&mqrq->brq)) {
+ mmc_retune_hold_now(host);
+ mmc_blk_rw_recovery(mq, req);
+ }
+
+ mmc_blk_urgent_bkops(mq, mqrq);
+
+ mmc_blk_mq_post_req(mq, req);
+}
+
static void mmc_blk_mq_complete_prev_req(struct mmc_queue *mq,
struct request **prev_req)
{
+ if (mmc_queue_direct_complete(mq->card->host))
+ return;
+
mutex_lock(&mq->complete_lock);

if (!mq->complete_req)
@@ -2208,19 +2253,43 @@ static void mmc_blk_mq_req_done(struct mmc_request *mrq)
struct request *req = mmc_queue_req_to_req(mqrq);
struct request_queue *q = req->q;
struct mmc_queue *mq = q->queuedata;
+ struct mmc_host *host = mq->card->host;
unsigned long flags;
- bool waiting;

- spin_lock_irqsave(q->queue_lock, flags);
- mq->complete_req = req;
- mq->rw_wait = false;
- waiting = mq->waiting;
- spin_unlock_irqrestore(q->queue_lock, flags);
+ if (!mmc_queue_direct_complete(host)) {
+ bool waiting;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ mq->complete_req = req;
+ mq->rw_wait = false;
+ waiting = mq->waiting;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (waiting)
+ wake_up(&mq->wait);
+ else
+ kblockd_schedule_work(&mq->complete_work);

- if (waiting)
+ return;
+ }
+
+ if (mmc_blk_rq_error(&mqrq->brq) ||
+ mmc_blk_urgent_bkops_needed(mq, mqrq)) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ mq->recovery_needed = true;
+ mq->recovery_req = req;
+ spin_unlock_irqrestore(q->queue_lock, flags);
wake_up(&mq->wait);
- else
- kblockd_schedule_work(&mq->complete_work);
+ schedule_work(&mq->recovery_work);
+ return;
+ }
+
+ mmc_blk_rw_reset_success(mq, req);
+
+ mq->rw_wait = false;
+ wake_up(&mq->wait);
+
+ mmc_blk_mq_post_req(mq, req);
}

static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
@@ -2230,7 +2299,12 @@ static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
bool done;

spin_lock_irqsave(q->queue_lock, flags);
- done = !mq->rw_wait;
+ if (mq->recovery_needed) {
+ *err = -EBUSY;
+ done = true;
+ } else {
+ done = !mq->rw_wait;
+ }
mq->waiting = !done;
spin_unlock_irqrestore(q->queue_lock, flags);

@@ -2277,6 +2351,10 @@ static int mmc_blk_mq_issue_rw_rq(struct mmc_queue *mq,
if (err)
mq->rw_wait = false;

+ /* Release re-tuning here where there is no synchronization required */
+ if (mmc_queue_direct_complete(host))
+ mmc_retune_release(host);
+
out_post_req:
if (err && host->ops->post_req)
host->ops->post_req(host, &mqrq->brq.mrq, err);
diff --git a/drivers/mmc/core/block.h b/drivers/mmc/core/block.h
index 6c0e98c1af71..5ad22c1c0318 100644
--- a/drivers/mmc/core/block.h
+++ b/drivers/mmc/core/block.h
@@ -12,6 +12,7 @@

enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req);
void mmc_blk_mq_complete(struct request *req);
+void mmc_blk_mq_recovery(struct mmc_queue *mq);

struct work_struct;

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 971f97698866..bcba2995c767 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -165,7 +165,10 @@ static void mmc_mq_recovery_handler(struct work_struct *work)

mq->in_recovery = true;

- mmc_blk_cqe_recovery(mq);
+ if (mq->use_cqe)
+ mmc_blk_cqe_recovery(mq);
+ else
+ mmc_blk_mq_recovery(mq);

mq->in_recovery = false;

diff --git a/drivers/mmc/core/queue.h b/drivers/mmc/core/queue.h
index f05b5a9d2f87..9bbfbb1fad7b 100644
--- a/drivers/mmc/core/queue.h
+++ b/drivers/mmc/core/queue.h
@@ -102,6 +102,7 @@ struct mmc_queue {
bool waiting;
struct work_struct recovery_work;
wait_queue_head_t wait;
+ struct request *recovery_req;
struct request *complete_req;
struct mutex complete_lock;
struct work_struct complete_work;
@@ -133,4 +134,9 @@ static inline int mmc_cqe_qcnt(struct mmc_queue *mq)
mq->in_flight[MMC_ISSUE_ASYNC];
}

+static inline bool mmc_queue_direct_complete(struct mmc_host *host)
+{
+ return host->caps & MMC_CAP_DIRECT_COMPLETE;
+}
+
#endif
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ce2075d6f429..4b68a95a8818 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -324,6 +324,7 @@ struct mmc_host {
#define MMC_CAP_DRIVER_TYPE_A (1 << 23) /* Host supports Driver Type A */
#define MMC_CAP_DRIVER_TYPE_C (1 << 24) /* Host supports Driver Type C */
#define MMC_CAP_DRIVER_TYPE_D (1 << 25) /* Host supports Driver Type D */
+#define MMC_CAP_DIRECT_COMPLETE (1 << 27) /* RW reqs can be completed within mmc_request_done() */
#define MMC_CAP_CD_WAKE (1 << 28) /* Enable card detect wake */
#define MMC_CAP_CMD_DURING_TFR (1 << 29) /* Commands during data transfer */
#define MMC_CAP_CMD23 (1 << 30) /* CMD23 supported. */
--
1.9.1

Next message: Adrian Hunter: "[PATCH V13 05/10] mmc: cqhci: support for command queue enabled host"
Previous message: Adrian Hunter: "[PATCH V13 04/10] mmc: block: Add CQE support"
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Next in thread: Adrian Hunter: "[PATCH V13 05/10] mmc: cqhci: support for command queue enabled host"
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